The present invention relates to a mixing device. More particularly, the invention relates to a mixing device for mixing fluids such as liquids, gases and fluid suspensions of particles, by the interaction of counter-rotating flows of fluids. This type of device is generally known as a swirl mixing device, the term "swirl" being generally used to refer to the circulating flow of the fluid in a mixing chamber.
Some prior art swirl mixing devices are known. Examples of such devices are shown in U.S. Pat. Nos. 981,098, 3,261,593 and 3,862,907. In these known devices fluids are directed into a cylindrical mixing chamber from inlet pipes having nearly tangetially directed outlets, such that the fluids tend initially to move around the outer wall of the chamber, and constrains (kinematically) eddies that must occur at the interface of the fluids to be mixed. This results in significant energy dissipation due to frictional losses as fluids impinge on the walls of the chamber. The fluids move more slowly as they approach the center of the chamber, resulting in a central "dead region". These effects reduce the ability of the fluids to mix thoroughly.
A swirl mixing device which reduces these effects is described in my earlier application, Ser. No. 205,147, where fluids are injected into a mixing chamber at spaced levels within the chamber, the fluids injected at different levels being injected in opposite rotational directions. The injection inlets are directed at a tangent to a circle of radius smaller than that of the mixing chamber, thus reducing the frictional energy losses due to interaction with the walls of the chamber.